Susceptor support structure and docking assembly

ABSTRACT

A chemical vapor deposition reactor or like apparatus including means for accurately sensing the temperature of a susceptor upon which substrates to be coated are positioned. Means for facilitating insertion and removal of the sensing means relative to the susceptor, and for facilitating movement of the susceptor from a reaction chamber to permit expedited loading or unloading of the susceptor, are included with the apparatus. A support structure is provided upon which the susceptor is movable relative to the reaction chamber. Externally of the reaction chamber a docking assembly is provided to receive the susceptor supporting structure and the susceptor during substrate loading and unloading. The temperature sensing means comprises a sheathed thermocouple, which is automatically and accurately positioned in the susceptor following each loading or unloading cycle.

United States Patent [191 Benzing et al.

[111 3,830,194 [451 Aug. 20, 1974 SUSCEPTOR SUPPORT STRUCTURE ANDDOCKING ASSEMBLY [75] Inventors: Walter C. Benzing, Saratoga; JamesMcDiarmid, San Jose, both of Calif.

[73] Assignee: Applied Materials Technology, Inc., Santa Clare, Calif.

[22] Filed: Sept. 28, 1972 [21] Appl. No.: 292,992

[52] US. Cl 118/9, 198/222, 214/23,

214/310, 266/5 R [51] Int. Cl. C23c 13/08 [58] Field of Search 118/5, 9,48-495,

[56] References Cited UNITED STATES PATENTS 3,098,763 7/1963 Deal et al.118/49.5

3,259,381 7/1966 Walker 266/5 R 3,441,000 4/1969 Burd ct al. 118/49.13,494,743 2/1970 Baughman et a1 ll8/49.l X 3,578,495 5/1971 Pammer et al118/48 X 3,617,371 11/1971 Burmeister, Jr. 118/48 X OTHER PUBLICATIONSlBM Technical Disclosure Bulletin, Apparatus For 44? Our TheIntroduction Of Substrates Into A Vapor Deposition System" Silvestri,Vol. 8, No. 5 [Oct. 1965] pp. 708, 709.

Primary Examiner-Morris Kaplan Attorney, Agent, or Firm-Flehr,l-lohbach, Test, Albritton & Herbert [5 7 ABSTRACT A chemical vapordeposition reactor or like apparatus including means for accuratelysensing the temperature of a susceptor upon which substrates to becoated are positioned. Means for facilitating insertion and re moval ofthe sensing means relative to the susceptor, and for'facilitatingmovement of the susceptor from a reaction chamber to permit expeditedloading or unloading of the susceptor, are included with the apparatus.A support structure is provided upon which the v i susceptor is movablerelative to the reaction chamber. Externally of the reaction chamber adocking assembly is provided to receive the susceptor supportingstructure and the susceptor during substrate loading and unloading. Thetemperature sensing means comprises a sheathed thermocouple, which isautomatically and accurately positioned in the susceptor following eachloading or unloading cycle.

15 Claims, 6 Drawing Figures Ago 3'.as0 .1s4

PAItmmuezomu Samara llllulllll l II Q MK vkuqwkkmk PAIENIEB auszo 1914sum 3 or 3 BACKGROUND OF THE INVENTION 1. Field of the Invention Thisinvention relates generally to the field of deposition of chemical filmson substrates. More particularly, the field of this invention involvesthe vapor deposition of epitaxial or like chemically deposited films onexposed surfaces of articles, such as silicon wafer substrates commonlyused in the electronics industry in the production of semiconductors andother devices. Still more particularly, the field of this inventioninvolves apparatus, such as gaseous chemical vapor deposition reactors,in which gaseous reactants are broughtinto contact with a heatedsubstrate supported by a susceptor within a cold wall reaction chamberto effect deposition of a desired film on the substrate.

This invention also relates specifically to the field of accuratelysensing the temperature of a susceptor during such a chemical depositionreaction, within a cold wall reaction chamber. This invention furtherrelates to the field of facilitating movement of a susceptor (duringloading and unloading of substrates thereon) relative to a temperaturesensor positioned within a reaction chamber in which film deposition iseffected.

2. Description of the Prior Art Substrates, such a silicon and likewafers, have been coated heretofore with epitaxial and other chemicallydeposited films, such as silicon dioxide or like films. However, so faras is known, the specific and improved procedure for sensing accuratelythe temperature of a susceptor on which substrates are supported duringchemical vapor deposition has been unknown heretofore. Furthermore, sofar as is known, the particular support structure and docking assemblydisclosed herein for facilitating loading and unloading of substrates ona susceptor prior to and following a chemical vapor deposition (CVD)reaction within a reactor chamber also have been unknown heretofore.

Heretofore the temperature of a susceptor during a cool wall CVDreaction was sensed by utilizing an optical instrument, such as anon-contact optical pyrometer through which the substrate was viewedfrom outside the reaction chamber. Such optical temperature sensingprocedures produce less than desirable results because film deposits,which interfere with accurate temperature sensing, frequently form onthe transparent walls of the reaction chamber. Furthermore, filmdeposits which may form on the susceptor also tend to defeat accuratetemperature sensing by changing the emissivity of the susceptor surfaceor as a result of optical interference effects in the case of depositedtransparent films. Additionally, other operating conditions encounteredin conjunction with a cool wall CVD reaction make optical pyrometricsensing methods less accurate than direct sensing using a thermocouplesensing device. I

While some use of thermocouple sensing means has been tried heretofore,the particular thermocouple arrangement illustrated herein (and thedocking assembly which makes utilization of such a thermocouplearrangement feasible) has been unknown heretofore. Prior thermocoupleutilizations were limited because of the inability to easily anduniformly relocate the thermocouple sheath relative to the susceptor,the temperature of which was being sensed during a CVD operation.

Thus, to the extent that thermocouples have been utilized heretofore tosense a susceptor temperature during a CVD reaction, the particularthermocouple positioning arrangement illustrated herein, combined withthe docking assembly provided to facilitate susceptor loading andunloading relative to the reaction chamber, have been unknownheretofore.

SUMMARY OF THE INVENTION This invention relates generally to an improvedapparatus and arrangement for sensing the temperature of a susceptorupon which substrates are supported during a chemical vapor depositionor like reaction in a reaction chamber. More particularly, thisinvention relates to means for positively and accurately orienting athermocouple sensor in conjunction witha substrate supporting susceptorin a CVD reaction chamber.

Still more particularly, this invention relates to improved means forfacilitating loading and unloading of substrates relative to a reactorby simplifying the positioning of a substrate supporting susceptorwithin a reaction chamber. Still more particularly, this inventionrelates to docking means provided in conjunction with a reactor utilizedduring chemical vapor deposition film coating of substrates in theproduction of semiconductor devices.

Heretofore, temperatures of the susceptor upon which substrates arefrequently supported during a CVD reaction have been sensed visuallythrough the utilization of optical pyrometric devices. Such opticaldevices do not give uniform or accurate temperature sensing results dueto the factors set out herein previously. Attempts heretofore toposition a thermocouple sensor in conjunction with a susceptor to obtainmore accurate temperature readings than are possible with an opticalsensing device have encountered difficulty because of prior inability toeasily and accurately relocate the thermocouple sensing head in the sameorientation relative to the susceptor which is to be sensed.

With the present arrangement, a thermocouple sensor is utilized whichmay be repeatedly, accurately and easily positioned in exactly the sameorientation relative to the susceptor being sensed so that accuratetemperature readings are insured. With the present invention, thesusceptor to be sensed is provided with a longitudinal bore in which athermocouple sensor is oriented when the susceptor is operativelypositioned within a reaction chamber. In that connection, the susceptoris supported upon support means which facilitates insertion and removalof the susceptor relative to the reaction chamber and which insuresaccurate positioning of the thermocouple sensor utilized therewith.

In that regard, the support means and the susceptor are movable as aunit relative to the reaction chamber interior and, when withdrawn fromthe reaction chamber, are positionable upon an improved docking assemblyprovided adjacent the reaction chamber. Such docking assembly includesguide means for facilitating movement of the support means from thereactor, with the susceptor thereon. Such docking assembly furtherinclude stop means for facilitating at least partial separation of thesusceptor from the support means during loading and unloading ofsubstrates from the susceptor.

Upon separating the susceptor from the support means therefor, suchsupport means remains at least partially positioned within the reactionchamber and in engagement with the thermocouple sensor to facilitatereinsertion of the sensor into the susceptor following loading ofsubstrates on the susceptor. By permitting separation of the susceptoronto a separate portion of the docking assembly, unloading and loadingof substrates may be effected at a more convenient location spacedsomewhat from the reaction chamber.

From the foregoing, it should be understood that objects of thisinvention include the provision of an improved arrangementfor'accurately sensing the temperature of an element, such as asusceptor utilized in a chemical vapor deposition reaction; theprovision of improved thermocouple sensing means which may be repeatedlypositioned in a predetermined location for accurate sensing temperatureof a susceptor movable relative thereto during loading and unloading ofa reaction chamber in which a CVD reaction is to be effected; theprovision of improved support means for a susceptor; the provision ofimproved docking means and a docking assembly adjacent a reactionchamber to facilitate handling of a susceptor and support means thereforduring loading and unloading of substrates therefrom; and the provisionof improved means for sensing the temperature of a susceptor in a CVDreaction chamber during epitaxial and like film coating of substratespositioned thereon. These and other objects of this invention willbecome apparent from a study of the following disclosure in whichreference is directed to the attached drawings.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a longitudinal sectionalview, largely schematic in nature, through a chemical vapor depositionreactor and the docking assembly of this invention positioned adjacentthereto.

FIG. 2 is a partial longitudinal sectional view of a portion of thereactor and docking assembly shown in FIG. 1 and illustrating asusceptor and support means therefor partially removed from the reactionchamber of the reactor. 4

FIG. 3 is a longitudinal sectional view corresponding generally to FIG.2 showing the susceptor fully removed from the reaction chamber.

FIG. 4 is a plan view, taken in the plane of line 4-4 of FIG. 1,illustrating details of construction of the susceptor and support meanstherefor.

FIGS. 5 and 6 are vertical sectional views through the docking assemblyillustrating the cooperation between.

the susceptonthe support means therefor, and the docking assembly, takenin the planesof lines 5-5 and 66, respectively.

DESCRIPTION OF THE PREFERRED EMBODIMENTS As noted previously, thesubject invention and its various aspects preferably are utilized withchemical vapor deposition (CVD) reactors in which epitaxial and likethin films are deposited chemically at elevated temperatures inconjunction with known procedures. In that regard, such reactions arecarried out in high temperature reactors which are operable attemperatures of, for example, 750 to l,300 C., as well as in lowertemperature reactors which are operable at temperatures of 350 to 750 C.In such reactors, thin chemical films of known types are deposited onsubstrates, such as silicon wafers, commonly utilized in the electronicsindustry in the manufacture of semiconductor devices. The exact type ofreaction chamber utilized and the heat source employed to heat thesubstrates to be coated therein may be of any known type.

In that connection, described by way of illustration hereinafter is aCVD reactor in which the heat source comprises a bank of high intensityradiant heat lamps positioned to heat a horizontally oriented reactionchamber and substrates positioned therein in the fashion disclosed inMcNeilly et al. US. Pat. 3,623,712, Epitaxial Radiation Heated Reactorand Process, dated Nov. 30, 1971. However, it should be understood thatsuch reference herein to the radiant heat source disclosed in saidMcNeiIly et al. patent is by way of illustration only and that otherpower sources, such as radio frequency (RF )induction heating coils alsomay be utilized.

Irrespective of the heat source employed, CVD reactions heretofore havebeen accompanied by difficulty in accurately sensing the temperature ofthe graphite or like susceptor commonly utilized to support substratesduring thin film coating. The present invention has been designed topermit accurate temperature sensing of such a supporting susceptorwithout utilizing optical p'yrometric devices as was the common practiceheretofore. 7

Additionally, the apparatus of the present invention utilizes improvedmeans in conjunction with the reaction chamber to facilitate insertionof the susceptor into and removal thereof from the reaction chamber tofacilitate positioning and removal of substrates from the susceptor whenthe same is located externally of the reaction chamber.

While the improved features of this invention, such as the temperaturesensor arrangement and the docking assembly to be described, haveparticular utility in conjunction with CVD reactions and reactorstherefor, it should be understood that the utility of this invention isnot limited to that particular field and that the same is utilizable inother installations in which accurate sensing of high temperature bodieswithin a chamber, plus the need to facilitate loading and unloading of abody to be heated in a chamber, is required. Thus, it should beunderstood that reference specifically herein to CVD reactors andreactions is by way of illustration, rather than by way of limitation.

With the foregoing general comments in mind, reference is directed tothe appended drawings, taken in conjunction with the followingdescription, for an understanding of the novel features incorporatedinto this invention.

Referring first to FIG. 1, the overall CVD apparatus with which thesubject inventive features are employed will be described. In thatconnection, the reactor illustrated in FIG. 1 employs a heat sourcewhich comprises a plurality of high intensity radiant heat lamps, suchas tungsten filament lamps each of which includes a transparent quartzenvelope and a halogen gas contained therein, preferably iodine, as willbe described in greater detail hereinafter. The radiation heated reactorshown is generally designated 1 and comprises an elongated housing,generally designated 2, defined by opposed end walls 3 and 4, opposedside walls (not specifically seen in FIG. 1) and a removable top closure6, the latter being slidable along or otherwise separable from the uppermargins of the side walls and end walls to permit access to the hollowinterior 7 of the housing.

Opposite ends of housing 2 are defined by the end walls 3 and 4 so thatthe interior 7 of the housing is completely enclosed in known fashion.However, access into the hollow interior may be had through at least oneend of the housing as may be necessary. A suitable door (not shown) maybe provided in either of the end walls 3 and 4 at any suitable locationso that access may be had to the housing interior as noted.

Preferably the inner surfaces of the confining end walls and side wallsof the housing, and of the top closure, are formed of a highly polishedreflecting material, such as polished sheet aluminum. Such reflectingsurfaces are provided to permit maximum utilization of the heatgenerated by the heat source to be described.

Such heat source in the illustrated embodiment is generally designated11 and extends longitudinally and laterally of the housing as seen inFIG. 1. The heat source is secured and positioned in place by fasteningthe same to suitable portions of the housing side walls in knownfashion. As noted, the heat source may be selected from one of severalavailable types but it is preferred that the same be defined by aradiant energy heat source which permits cool wall operation of thereactor in the manner described in said McNeilly et al., patent.

In that regard, the radiant heat source illustrated comprises a bank ofhigh intensity lamps capable of producing and transmitting radiant heatenergy at a short wave length, such as approximately 1 micron or less.In the embodiment illustrated, such heat source comprises a plurality ofsuch lamps arranged in a bank, each lamp being designated 12. In thatconnection, reference is directed to the aforementioned McNeilly et al.,patent for an understanding of the construction and function of such abank of radiant heat lamps and the manner in which radiant heat energyis produced thereby. Such lamps are commercially available from sourcessuch as the Aerometrics division of Aerojet General Corporation and fromthe General Electric Corporation.

As noted in the aforementioned patent, such lamps, as shown in FIG. 1hereof, are constructed to be mounted upright in their sockets inmounting block 13, but in other embodiments, also as shown in suchpatent, the lamps may be oriented in other orientations by utilizingother mounting block constructions and other lamp configurations. Suchradiant heat lamps operate at very hightemperatures, for example 5,000to6,000 F. and means are provided in conjunction with the housing and withthe lamp mounting block 13 to cool the same.

In that regard, cooling arrangements of the type described in saidMcNeilly et al., patent may be employed, including cooling fluidconduits (not shown) through which water or like cooling medium may becirculated in conjunction with the side walls of the housing. Suchconduits may be operatively connected with any suitable supply ofcooling fluid and a disposal system therefor in known fashion.Similarly, cooling water conduits 16 may be provided in conjunction withthe top closure 6 of the housing as seen in FIG. 1.

Additionally, means for cooling the mounting block for the bank of lampsalso may be provided including entry and exit fluid conduits l7 and 18which communicate with fluid passages formed in the lamp mounting block.To further assist cooling of the lamps and the mounting block, as wellas the remainder of the reactor apparatus, a plenum chamber 19 isprovided in the base of the lamp mounting block which communicates withthe sockets in which the lamps are mounted in the block 13 in thefashion described in the aforementioned McNeilly et al., patent. Suchplenum is operatively connected with an inlet conduit 21 for coolingair. Thus, by introducing air through conduit 21 into plenum chamber 19,the same may pass upwardly through the sockets in which the lamps aremounted and into the open interior 7 of the housing for subsequentremoval through an exhaust conduit 22 positioned adjacent the topclosure 6 of the housing.

In that regard, in applicants assignees Anderson et al., applicationSer. No. 237,698 entitled Improved Radiant Heat Energy Lamp Assembly,filed Mar. 24, I972, improved reflector means for effecting cooling ofhigh intensity radiant heat lampsare lamps are as well as an improvedlamp mounting block and lamp assembly used in conjunction therewith. Ifpreferred, the radiant heat source shown in said Anderson et al.application may be utilized in place of the heat source illustratedherein.

Positioned within the hollow interior of housing 7 is the structurewhich definesthe reaction zone in which thin film chemical vapordeposition may be effected on substrates positioned therein. Suchreaction zone is defined by and comprises a reaction chamber delimitedby an elongated horizontally extending tubular structure 26 formed froma material which is transparent to heat energy generated by the heatsource 11. In its preferred form, such reaction chamber structure isrectangular in transverse cross section and has its four integral wallsformed from quartz which is transparent to radiant energy transmitted atthe short wave length noted previously. Such quartz tube may vary indimensions according to particular production needs. However, one suchtube having dimensions of 2 inches by 6 inches, with the length beingdetermined in accordance with production requirements, may be employed.

As seen in FIG. 1, one end of the reactor tube 26 is operativelyconnected at 27 with exhaust means in the form of a conduit which isfused or otherwise secured to the main body of the tube in knownfashion. Such exhaust conduit in turn is connected with an exhaustsystem provided for the reactor apparatus in known fashion.

At its opposite end, gaseous reactants to be employed in the filmcoating procedure are introduced into the reaction chamber tube throughinlet means which, in the embodiment illustrat ed, comprises an inletconduit 28 which is connected any suitable source of gaeous reactants tobe introduced into the reaction zone in known fashion. In that regard,conduit 28 introduces gaseous reactants into a chamber 29 defined by abaffle wall 31 secured to the housing to overlie the tube 26 in anysuitable fashion, and positioned in sealing contact therewith.

An inlet aperture 32 is provided in the upper wall of the quartz tube inalignment with chamber 29 so that gaseous reactants introduced into thechamber may pass therefrom into the reaction zone without escaping intothe hollow interior of the housing. Thus, gaseous reactants passing intothe reaction zone may perform their intended chemical vapor depositionfunction on heated substrates positioned in the reaction zone. The spentreactants pass from the reaction zone through conduit 27 mentionedpreviously. The nature of the chemical reaction effected in the reactionzone is well known in the CVD art and need not be discussed here.

Substrates to be coated in the reactor are supported within the reactionchamber on an elongated support defined by a slab-like susceptor 36defined by a body of graphite or like opaque heat absorbing material.Such substrates, as noted previously, normally comprise a series of thinsilicon or like wafers 37 arranged in one or more parallel rows alongthe upper surface of the susceptor as seen in FIGS. 4 through 6. Thesize of the susceptor is correlated to the size of the quartz tubereaction chamber 26 and may vary to meet particular commercial needs.

As noted, the susceptor 36 comprises an elongated body which is opaqueto radiant heat energy at the wave length transmitted by the radiantheat source 11. The susceptor illustrated includes means to accommodateat least one temperature sensor in conjunction therewith. Such meanscomprises a longitudinal recess or base 38 extending from one end 39thereof towards the opposite end 41 thereof. In that regard, it shouldbe noted bore 38 enters the susceptor body from the downstream or exitend of reaction chamber so that gaseous reactants do not flow directlyinto the bore as they travel toward exhaust conduit 27.

It will be noted from FIGS. 2 and 3 that bore 38 extends substantiallythe full length of the susceptor body but terminates short of end 41thereof. It is in such bore that the temperature sensor utilized withthis invention is positioned when the susceptor is operatively locatedwithin the reaction chamber. Bore 38 preferably is positioned to extendlongitudinally-of the susceptor along the longitudinal axis thereof, asbest seen in FIG. 6. It should be understood, however, that, while onesuch bore to accommodate a single thermocouple sensor device has beenillustrated, if desired, plural bores and plural sensors (arranged inparallel relationship) may be utilized, depending upon the nature andnumber of the temperature readings to be obtained.

Susceptor 36 is supported in spaced relationship above the bottom wall42 of the reaction chamber tube 26 by support means defined by a supportstructure of particular illustrated, construction. In that regard, suchsupport structure comprises with any slidable sled member, gaseousdesignated 43, which is formed from quartz which is transparent to theradiant heat energy emitted by the heat source described.

As best seen in FIG. 4 the support sled 43 is defined by two quartzplates 44 and 46 which define the opposite ends of the sled. Extendingbetween the end plates are a pair of generally circular cylindricalelongated rails 47 and 48 which are fused or otherwise joined in spacedparallel relationship to the plates 44 and 46.

As seen from FIGS. 1 through 3, plate 44 at one end of the sled is ofsubstantially greater thickness than plate 46 at the other end. Therails 47 and 48 are fused to the underside of plate 44 and extend intoreceiving slots provided therefor in plate 46 as best seen in FIG. 4.Also, as noted from FIGS. 2 and 3, the rails 47 and 48 are of greaterthickness than plate 46. As a result, the plates are spaced slightlyabove the bottom wall 42 of the reaction chamber. Thus, as the sled ismoved longitudinally of the reaction chamber between the positions shownin FIGS. 1, 2 and 3, only the rails contact the bottom wall of thereaction chamber to obviate undue wear and damage thereto duringrepeated movement of the sled in and out of the reaction chamber.

As noted from FIGS. 4 and 6, susceptor 36 is provided with a pair oflaterally spaced parallel generally V-shaped grooves 49 and 51 in itsunder surface. The lateral spacing of the axes of grooves 49 and 51corresponds to the lateral spacing of the axes of rails 47 and 48 of thesled and the susceptor is thus longitudinally slidable on the sled railsas will be described. In that connection it should be noted from FIG. 5that rails 47 and 48 also project above the upper surface of end plate46 of the sled so that the susceptor 36 may move longitudinally overplate 46 without interference therefrom.

As seen in FIG. 4, the sled is provided with an opening 53 in plate 46and susceptor 36 is provided with an opening 54 adjacent end 41 thereof.Such openings are provided so that the susceptor and sled may be movedrelative to the reaction chamber and relative to each other duringloading and unloading operations. A tool is utilized for that purpose aswill be described.

Referring to FIG. 1 taken in conjunction with FIGS. 2 and 3, it will benoted that a temperature sensor in the form of an elongated sheathedthermocouple device generally designated 56, extends through and itmounted in a gas tight seal 57 provided at the discharge end of thequartz tube 26. The thermocouple sensor is connected in known fashion bylead wire 58 with any suitable temperature sensing and indicatingapparatus (not shown).

The thermocouple device is of elongated construction and immovablyextends the major portion of the length of the reaction chamber tube asseen. In that regard, the thermocouple extends through a guide bore 59provided in plate 44 of the sled into bore 36 in susceptor. Thus, duringmovement of the sled relative to the reaction chamber and relative tothe thermocouple, the thermocouple will slidably move through bore 59and will be at least partially supported thereby to the extent thatsupport is necessary to preclude damage of the thermocouple. As will benoted from FIG. 3, when the susceptor is fully removed from the reactionchamber as will be described, at least a portion of the sled remainswithin the reaction chamber so that the sensing end 61 of thethermocouple remains in bore 59 of the sled plate 44 and is supportedthereby.

In that connection, it will be noted from FIG. 2 that when the susceptoris operatively positioned on the sled within the reaction chamber, theend 39 of the susceptor abuts against a shoulder formed by the enlargedplate 44 of the sled. Thus, by moving the susceptor over the rails 47and 48 until end 39 of the susceptor strikes the shoulder of plate 44,proper positioning of the susceptor on the sled is effected. Thereafter,by sliding the sled, with the susceptor thereon as a unit, to apredetermined orientation within the reaction chamber, the thermocouplesensing end 61 maybe positioned at the desired location within thesusceptor to provide the precise temperature sensing function sought.

In the manner to be described, repeated removal and reintroduction ofthe susceptor relative to the reaction chamber during sequential batchoperations of the reaction chamber results in the thermocouple beingprecisely oriented in the exact location desired each time so thateffective and uniform temperature sensing is insured.

As noted previously, an important aspect of this invention isincorporated into docking means defined by an assembly positionedadjacent to one end 66 of the reaction chamber. Access to the reactionchamber of the illustrated reactor is obtained by slidably removing aclosure plate 67 which is movable late'rally over enlarged flanges 68formed integral with the upper and bottom walls of the reaction chamber.With the closure plate 67 removed as seen in FIGS. 2 and 3, the sled andsusceptor carried thereon may be' removed from or returned to theiroperative position within the reaction chamber.

In that regard, the docking assembly, generally designated 71, isoperatively positioned adjacent the end 66 of the reaction chamber inany suitable fashion. Such docking assembly may be self-supporting ormay be supported upon another supporting surface in any suitablefashion. In the embodiment illustrated, such docking assembly isschematically illustrated as being generally self-sustaining with theupper operative surface thereof generally in alignment with the bottomwall 42 of the reaction chamber tube 26.

An important feature of the docking assembly is the fact that the samecan selectively handle both the sled and the susceptor even though thesled and susceptor generally lie in different horizontal planes. Thatis, the docking assembly is provided with stop means designed tocooperate with the susceptor and the sled to selectively position eachof those components as the sledsusceptor combination is removed from thereaction chamber.

In that regard, referring to FIGS. and 6, it will be noted that thedocking assembly comprises a pair of laterally spaced metal structuralpanel members 72 and 73 which are supported in any suitable fashion by asupporting framework. Such structural members 72 and 73 compriseslongitudinally extending oppositely bent rail section 74 and 76respectively which extend the length of the assembly. Such rail sectionsinclude horizontal portions 77 and 78, respectively, and integralupright or vertical portions 79 and 81, respectively. The rail portions79 and 81 define lateral margins of the docking assembly and preventlateral separation of the sled therefrom as seen in FIGS. Sand 6.

Extending between structural members 72 and 73 are the reaction tube end66 and is defined by a plurality of pivot shafts 82 rotatably mounted inbearings (not shown) in the opposed structural members 72 and 73.Mounted adjacent opposite ends of each of the shafts 82 (as seen in FIG.5) are a pair of grooved circular guide rollers 83 and 84 respectively.Spacing of rollers 83 and 84 from each other corresponds to the lateralspacing of the aforementioned rails 47 and 48 of the sled. Thus, whenthe sled is withdrawn from the reactor from the position shown in FIG. 1to the position shown in FIG. 2, rails 47 and 48 are engaged with therollers 83 and 84 and are guided thereby during movement of the sledrelative to the reaction chamber.

Such sled movement may continue until leading end plate 46 of the sledstrikes stop means on the docking assembly defined by the second seriesof rollers, as seen in FIG. 2. In that regard, the second set of rollersis defined by a plurality of spaced pivot shafts 86 which are rotatablymounted in bearings (not shown) on the opposite structural members 72and 73 of the docking assembly. The shafts 86, as seen from FIGS. 2 and3, are mounted in a slightly elevated plane compared to the plane inwhich shafts 82 of the first series of rollers are positioned.

As seen in FIG. 6, a pair of laterally spaced rollers 87 are provided oneach of the shafts 86. Such rollers have a smooth periphery as comparedto the grooved periphery of the aforementioned rollers 83 and 84. Therollers 87 have their upper peripheries lying on a higher vertical leverrelative to the upper peripheries of the grooved rollers 83 and 84. Thedifference in vertical spacing is effected so that susceptor 36 may beslidably moved from rails 47 and 48 of the sled over plate 46 onto therollers 87, as seen in FIG. 3. Thus, for all intents and purposes, thesusceptor may be slidably separated from the sled to facilitate loadingand unloading of substrates therefrom.

It will be noted that the docking assembly includes the aforementionedstop means to limit longitudinal movement of the sled (with thesusceptor thereon) as the sled is moved onto the docking assembly. Inthat regard, the second series of rollers 86, 87 define such stop meansin that the first rollers of that series are engaged by the plate 46of'the sled as the sled is withdrawn. When such engagement is effected,movement of the sled terminates and thereafter the susceptor may beslidably moved longitudinally over rails 47 and 48 onto the rollers 87as seen in the position of FIG. 3.

When the susceptor is pulled to the position seen in FIG. 3, it isentirely free of the reaction chamber and the substrates which had beencoated in the reaction chamber may be removed from the susceptor, and asubsequent quantity of substrates may be loaded out of the susceptor.The susceptor is then ready for reinsertion into the reaction chamberfor a repetition of the CVD cycle.

It should be noted that the different elevations in which the rollers ofthe first and second series are mounted insure that the susceptor may beslidably moved directly from the sled onto the rollers 87.

It will be understood as seen in FIG. 2 that a suitable tool, in theform of an elongated rod 91 having a bent end 92 thereon, may beutilized to withdraw and reinsert the sled from the reaction chamber,and to move the susceptor relative to the sled. Such rod has its end 92inserted into the respective openings 53 and 54 of;

the sled and susceptor as noted previously to effect such movement ineither direction.

While stop means for the susceptor on the assembly are not specificallyrequired, if desired, the free ends of the guide rails 79 and 81 mayhave tabs (not shown) bent inwardly therefrom into the path of thesusceptor to prevent inadvertent removal of the susceptor from the endof the docking assembly by an inattentive apparatus operator.

Also, preferably provided in conjunction with the docking assembly aremeans to temporarily limit reverse movement of the sled into thereaction chamber as the susceptor is moved over the sled from theposition of FIG. 3 back to the position of FIG. 2. That is, because ofthe frictional engagement between the susceptor and the rails of thesled, movement of the susceptor over such rails normally tends to movethe sled with the susceptor. Because movement of the sled is not desireduntil the susceptor comes into engagement with the positioning shoulderof the plate 44 of the sled as seen in FIG. 2, it is desired to providemeans to temporarily hold the sled in the position seen in FIG. 3 untilthe susceptor is moved to the position seen in FIG. 2.

Such means comprises a stop lug 96 provided on each of the guide railportions of the docking assembly. Each stop lug is secured in place byscrews or rivets as seen in FIG. 5. Each stop lug is positioned in thepath of movement of plate 46 of the sled and each lug is provided with apair of tapered edge portions 97 and 98, which lie on opposite sides ofa generally flat upper edge portion 99.

Thus, when the sled comes in contact with the respective stop lugs,plate 46 will ride upwards over the inclined edge portion 97 and overthe straight edge portion 99 until the plate clears the other taperededge portion 98. At that time, the plate will then drop behind thetapered portion 98 to the position seen in FIG. 2. Thus, reversemovement of the sled toward the reaction chamber is temporarilyprecluded by the lugs 96. However, once the susceptor is in place on thesled as seen in FIG. 2, movement of the sled with the susceptor thereonmay be easily effected by continuing to push the susceptor with tool 91so that the sled rides over the inclined edge 98 and subsequently freesitself of engagement with the stop lugs 96.

With the arrangement shown, uniform positioning of the sensing end 61 ofthe thermocouple may be easily and accurately effected following eachloading and unloading cycle of the susceptor. In that regard, preferablytool 91 is provided with indexing means thereon so that a visualdetermination can be made to insure that the sled, with the susceptorthereon, is properly oriented. In the embodiment illustrated, the toolis provided with a slidable indicating collar 101 held in place thereonby a set screw 102, as seen in FIGS. 1 and 2. By utilizing the tool topush the susceptor/sled combination back into the reaction chamber,proper positioning of the sled, and therefore of the susceptor also, maybe visually determined by bringing the collar into alignment with theouter edge of the reactor chamber tube end 66. When thus properlyoriented, the sensing end 61 of the thermocouple 56 is properlypositioned within the bore 36 in the susceptor body. Such properorientation may be repeated easilyand readily follow ing eachload-unload cycle of movement of the sled and susceptor.

In that connection, when the sled is moved from-the position shown inFIG. 3 to the position shown in FIG. 1, proper longitudinal orientationof the sled witin the tube is insured because of the rails 47 and 48 ofthe sled are in contact with the guide'rollers 83 of the dockingassembly until the time when the sled passes from engagement with theguide rollers. Thus, lateral misalignment of the sled in ,the reactortube-26 is precluded until the sled is properly positioned within thereaction chamber.

In the embodiment illustrated in FIGS. 1 through 3, a single temperaturesensing thermocouple is illustrated, that is, one which sensestemperatures at only one location namely, at the sensing end 61 thereof.By way of illustration, reference is directed to FIG. 4 in which amodified thermocouple configuration is illustrated, designated 56. Suchthermocouple is capable of sensing temperatures at more than onelocation and, in that regard, comprises a multiple "thermocouplestructure, preferably encased in a single thermocouple sheath. Themodified thermocouple contructuion 56' includes plural sensing ends,(three in number) designated I06, 107 and 108 respectively. Such sensingends are oriented when the susceptor is operatively positioned so thattemperature readings adjacent opposite ends of the susceptor andgenerally centrally thereof may be determined simultaneously. Thus,thermocouple structures of known constructions may be utilized toprovide multiple readings in a structural arrangement of the type shownin FIG. 4.

Having thus made a full disclosure of a preferred embodiment of thesubject invention, reference is directed to the appended claims for thescope of protection to be afforded thereto.

We claim:

1. In a chemical vapor deposition reactor or like apparatus, thecombination comprising A. a reaction chamber in which chemical vapordeposition is to be effected on substrates,

B. a supporting structure movably positioned within said chamber andbeing selectively removable therefrom,

C. a susceptor positioned on, supported by, and movable with saidsupporting structure on which said substrates are positionable,

l. a recess extending longitudinally of said susceptor from an endthereof,

D. a temperature sensor projecting into said susceptor recess when saidsupporting structure and said susceptor thereon are operativelypositioned within said chamber, and

E. means supporting said temperature sensor in a predetermined fixedorientation within said chamber and maintaining said sensor in suchorientation as said supporting structure and said susceptor are movedrelative to said chamber during loading or unloading of substratesrelative to said susceptor.

2. The apparatus of claim 1 which further includes F. means between saidsupporting structure and said susceptor for maintaining said susceptorproperly aligned with said supporting structure during relative movementtherebetween.

3. The apparatus of claim 2 in which said means comprises interfittinglongitudinal rails and grooves between said supporting structure andsaid susceptor which permit longitudinal sliding movement therebetweenand preclude lateral movement therebetween.

4. The apparatus of claim 3 in which said rails are provided on saidsupporting structure and said grooves are formed in the undersurface ofsaid susceptor.

5. The apparatus of claim 1 which further includes F. stop shouldermeans on said supporting structure against which said susceptor isengagable to properly position said susceptor thereon when saidsupporting structure with said susceptor thereon are operativelypositioned within said chamber.

6. The apparatus of claim in which said stop shoulder means comprises anenlarged shoulder against which an end of said susceptor is engagable,said shoulder having a guide opening therethrough through which saidtemperature sensor extends into said susceptor recess.

7. The apparatus of claim 1 which further includes F. reactant gas inletmeans and spent reactant gas outlet means in operative communicationwith said chamber,

G. said susceptor being oriented in said chamber so that said susceptorrecess therein opens in a direction facing away from said gas inletmeans so that reactant gases do not flow directly into said susceptorrecess.

8. The apparatus of claim 1 which further includes F. a docking rackassembly adjacent said reaction chamber for receiving said supportingstructure and said susceptor thereon when removed from said chamber forsubstrate loading or unloading.

9. The apparatus of claim 8 in which said docking rack includes twospaced docking surfaces for receiving said supporting structure and saidsusceptor separately thereon.

10. The apparatus of claim 9 in which said docking rack further includesguide rollers on each of said surfaces to facilitate movement of saidsupporting structure and said susceptor thereover.

1 1. The apparatus of claim 10 in which said rollers on one of saidsurfaces are grooved to interfit with rails provided on said supportingstructure.

12. The apparatus of claim 8 in which said docking rack assembly furtherincludes stop lug means to temporarily preclude movement of saidsupporting structure over said docking rack assembly as said susceptoris being moved over said supporting structure.

13. The apparatus of claim 9 in which one of said spaced dockingsurfaces defines stop means to limit movement of said supportingstructure over said other docking surface.

14. The apparatus of claim 1 in which said supporting structurecomprises a slidable sled having a plate at one end thereof throughwhich said temperature sensor extends, said plate maintaining an end ofsaid sensor properly oriented when such end is removed from saidsusceptor recess in response to movement of said susceptor over saidsled.

15. The apparatus of claim 1 in which said supporting structurecomprises a slidable sled defined by a pair of spaced plates having apair of laterally spaced rails extending therebetween over which saidsusceptor slides during relative movement between said sled and saidsusceptor.

A UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION 3,830,194October 9, 1974 Patent No.

Inventor(s) Walter C. Benzing & James McDiarmid It is certified thaterror appears in the above-identified patent and that said LettersPatent are hereby corrected as shown below Title Page, {73] "SantaClare" should be -S anta Clara--.

Column 6, Line 25, "lampsarelamps" should be --lamps are illustrated--.I

Column 6, Line 60, "illustrat ed" should be illustrated--.

Column 7, Line 54, "illustrated," should be -configuiiration and-'-. 1

Column 7, Line 57, "gaseous" should be ----generally-. 7

Column 8, Line 67, "maybe" should be may be-.

Column 10, Line 20, "lever" should be '--level-.

Signed and sealed this 11th day of February 1975.

(SEAL) Attest:

RUTH C. MASON Attesting Officer 0; MARSHALL DANN Commissioner of Patentsv and Trademarks

1. In a chemical vapor deposition reactor or like apparatus, thecombination comprising A. a reaction chamber in which chemical vapordeposition is to be effected on substrates, B. a supporting structuremovably positioned within said chamber and being selectively removabletherefrom, C. a susceptor positioned on, supported by, and movable withsaid supporting structure on which said substrates are positionable, 1.a recess extending longitudinally of said susceptor from an end thereof,D. a temperature sensor projecting into said susceptor recess when saidsupporting structure and said susceptor thereon are operativelypositioned within said chamber, and E. means supporting said temperaturesensor in a predetermined fixed orientation within said chamber andmaintaining said sensor in such orientation as said supporting structureand said susceptor are moved relative to said chamber during loading orunloading of substrates relative to said susceptor.
 2. The apparatus ofclaim 1 which further includes F. means between said supportingstructure and said susceptor for maintaining said susceptor properlyaligned with said supporting structure during relative movementtherebetween.
 3. The apparatus of claim 2 in which said means comprisesinterfitting longitudinal rails and grooves between said supportingstructure and said susceptor which permit longitudinal sliding movementtherebetween and preclude lateral movement therebetween.
 4. Theapparatus of claim 3 in which said rails are provided on said supportingstructure and said grooves are formed in the undersurface of saidsusceptor.
 5. The apparatus of claim 1 which further includes F. stopshoulder means on said supporting structure against which said susceptoris engagable to properly position said susceptor thereon when saidsupporting structure with said susceptor thereon are operativelypositioned within said chamber.
 6. The apparatus of claim 5 in whichsaid stop shoulder means comprises an enlarged shoulder against which anend of said susceptor is engagable, said shoulder having a guide openingtherethrough through which said temperature sensor extends into saidsusceptor recess.
 7. The apparatus of claim 1 which further includes F.reactant gas inlet means and spent reactant gas outlet means inoperative communication with said chamber, G. said susceptor beingoriented in said chamber so that said susceptor recess therein opens ina direction facing away from said gas inlet means so that reactant gasesdo not flow directly into said susceptor recess.
 8. The apparatus ofclaim 1 which further includes F. a docking rack assembly adjacent saidreaction chamber for receiving said supporting structure and saidsusceptor thereon when removed from said chamber for substrate loadingor unloading.
 9. The apparatus of claim 8 in which said docking rackincludes two spaced docking surfaces for receiving said supportingstructure and said susceptor separately thereon.
 10. The apparatus ofclaim 9 in which said docking rack further includes guide rollers oneach of said surfaces to facilitate movement of said supportingstructure and said susceptor thereover.
 11. The apparatus of claim 10 inwhich said rollers on one of said surfaces are grooved to interfit withrails provided on said supporting structure.
 12. The apparatus of claim8 in which said docking rack assembly further includes stop lug means totemporarily preclude movement of said supporting structure over saiddocking rack assembly as said susceptor is being moved over saidsupporting structure.
 13. The apparatus of claim 9 in which one of saidspaced docking surfaces defines stop means to limit movement of saidsupporting structure over said other docking surface.
 14. The apparatusof claim 1 in which said supporting structure comprises a slidable sledhaving a plate at one end thereof through which said temperature sensorextends, said plate maintaining an end of said sensor properly orientedwhen such end is removed from said susceptor recess in response tomovement of said susceptor over said sled.
 15. The apparatus of claim 1in which said supporting structure comprises a slidable sled defined bya pair of spaced plates having a pair of laterally spaced railsextending therebetween over which said susceptor slides during relativemovement between said sled and said susceptor.